Abbreviations S3, S4, S5... used to be used for the Speeds. Now I don't know if you're talking about Speeds, Souls, Sonics or Stokes!? One thing I notice, FS kite prices increase faster than my salary. In fact the prices are beyond silly. I guess they have enough wealthy customers, that they don't m...

I prefer riding smaller board with appropriate kite size for the conditions.
Some times the wind is not persistent and blows eg. 13-18 knots for 10 minutes, than 15-25 for 10 than back to 13-18. The top end is to strong for my 18m2, so I would go with 13m2 and long narrow board.